St. John's weather in September
September in St. John's: sweltering, rainy, with clean air — fine if you can take 20 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#12 of 12 months in St. John's · #701 of 1413 destinations to visit in September · comfort 80/100 (tier A)
- Days
- 32°C
- Nights
- 25°C
- Wet days
- 20
- Sun
- 10.8 h
- Humidity
- 79%
- Daylight
- 12 h

Traveller notes on St. John's in September
Other months in St. John's
Forum posters describe October as usually Antigua's wettest month, though posters are quick to add that doesn't mean much by the island's generally dry standards - evenings stay warm and humid around 75F, days remain hot enough for sunbathing, and the island still sees roughly 7 hours of sunshine on an average day. Posters describe rain as often torrential when it comes but rarely long-lasting, and note Antigua's central mountain range creates a genuine 'dry side' and 'rainy side': the south and southwest see meaningfully more rain than the north and northeast, where St. John's itself sits, and which can go weeks without significant rain even in October. Posters are direct that October remains technically within hurricane season, adding genuine uncertainty on top of the routine rain pattern. Posters generally rate October as St. John's own driest-side experience of Antigua's wettest month, warm and mostly sunny with real but often brief rain and a background hurricane-season risk.
Forum posters consistently describe April as pleasantly hot and one of the drier months on an island that's already fairly dry overall, with daytime temperatures typically in the low-to-mid 80sF and evenings only a few degrees cooler. Posters are direct that any daytime rain usually passes quickly - a 'rain' forecast here typically means 10-15 minutes of showers followed immediately by sunshine again - and consistently warn not to trust online weather forecasts for Caribbean islands, which tend to over-predict rain. Posters also flag real geographic variation from Antigua's central mountain range, with a noticeably rainier south/southwest side and a drier north/northeast side that can go weeks without rain. Posters generally rate April as a good, comfortable month to visit St. John's and the wider island.
Add your own note from St. John's's card on the map.
St. John's climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in St. John's in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Quietschool holidays in 2 of the markets that fill it, one of its worst months for weather(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for St. John's's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherSt. John's's weather doesn't swing hard through the year — comfort stays fairly steady in every month.
What's on in St. John's in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Hazard
Hurricane season
1 Jun – 30 NovAntigua sits where the Atlantic storms make their first landfall; Irma flattened Barbuda in September 2017. Most of the season passes uneventfully, and rates from August to October are the lowest of the year for that reason. Source ↗
Nearby, and something's on
Within 300 km of St. John's — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is St. John's?
St. John's in September — FAQ
- Is September a good time to visit St. John's?
- September in St. John's: sweltering, rainy, with clean air — fine if you can take 20 rainy days. It ranks #12 of 12 months for St. John's on SeasonMap's comfort score (80/100).
- What is the weather like in St. John's in September?
- In September, St. John's averages a daily high of 31.7°C and a low of 25°C, with about 128.2 mm of rain over roughly 19.6 rainy days.
- What is the air quality in St. John's in September?
- St. John's has a mean US Air Quality Index of about 37 in September.
Within 300 km: Philipsburg's Sea turtle nesting around 1 Apr – 30 Nov.